The finding suggests that a vaccine for human papillomavirus may be working.
Precancerous cervical lesions are on the decline among young women in Connecticut, the first indication nationally that a vaccine for human papillomavirus (HPV) types 16 and 18 may be working.
Researchers led by Linda M. Niccolai, an associate professor at the Yale School of Public Health, used a statewide surveillance registry to examine the incidence of high-grade cervical lesions in women ranging from 21 to 39 years old. Cervical and other types of genital and oropharyngeal cancers are known to be caused by HPV. A vaccine to fight HPV infections was introduced in 2006.
Use of the vaccine has risen sharply to include 61 percent of the state’s adolescent female population who had received at least one dose of the three-dose regimen. The six-member research team found that the incidence of precancerous lesions fell from 834 per 100,000 in 2008 to 688 by 2011 in the 21- to 24-year-old age group.
The findings are consistent with the results of studies conducted in Australia and Europe.
Comparable declines, however, were not found for other age groups in Connecticut, including women ranging in age from 25 to 39 years. The researchers also discovered that the declines were not as pronounced among Black and Hispanic women and among women living below the federal poverty line.
“While the decline in high-grade cervical lesions overall is exciting to see after only five years of vaccine availability, we need to be concerned about disproportiate impact for minorities and low-income women that are most affected by cervical cancer,” Niccolai said.
Reasons for this disparity are not clear, but may include different vaccination or screening rates, or different distributions of HPV types in these populations.
HPV types 16 and 18 are associated with nearly 70 percent of cervical cancers. The vaccine is recommended for routine use among 11- to 12-year-old adolescents and as a “catch-up” vaccination through the age of 26.
Connecticut and four other states are participating in similar surveillance activities to monitor HPV vaccine impact. In Connecticut, it is handled through the Yale office of the CT Emerging Infections Program.
While the use of HPV vaccine has risen steadily within the past several years, Niccolai said that substantial room for improvement remains.
“Rates of HPV vaccination in the United States lag far behind other countries including the UK and Australia, and we need to develop programs to increase coverage with this safe and effective vaccine,” she said.
The findings were published in the journal Cancer Epidemiology Biomarkers & Prevention.